Many devices are known for facilitating exercises done for therapy, conditioning or physical training. Other than variable resistance training equipment, these devices have not usually offered much adjustability to allow for exercises at different degrees of difficulty. Also, many of these devices have been dedicated to very specific exercises and therefore do not justify a significant investment of space and financial resources for such a narrow purpose.
Some exercise devices require a person to maintain balance and equilibrium. A large inflatable ball (for example, 65 cm) known as a Swiss ball, has been used for this purpose. While the ball is useful for certain stability training exercises, standing upon the ball or staying atop the ball requires a high degree of skill and is inappropriate for most.
In U.S. Pat. No. 4,801,140 a person suffering from a physical disability can stand on the flat side of a non-inflatable molded foam hemisphere to practice balancing. The practical disadvantage of this design is that a high degree of skill is required before someone can actually stand on such an unstable platform. Without assistance from a therapist or additional balancing accessories, this platform is accessible only to trained athletes.
In U.S. Pat. No. 5,810,703 the underside of a small board is fitted with a smaller spherical projection. The relatively small diameter of the spherical projection tends to make the board relatively unstable. The height of the spherical projection can be set to one of three discrete settings. Overall, the adjustment has little range and resolution. Also, the projection, if inverted to face upwardly, is too small to allow a person to perform an exercise while placing weight on the projection.
An inflated cushion in the shape of a disk (sold under the name DuraDisk through C.H.E.K. Institute) has been described as useful for certain exercises. This cushion is described as needing no inflation, but the product is shipped with an inflation valve that the user has access to. A separate wooden platform, 20 inches in diameter, is sold for the purpose of placing the platform over the cushion to create a balance board. This cushion is relatively flat and therefore offers little challenge to a user. It is not useful for the inflatable disk to be placed on the board as this would offer no advantage over putting the inflatable disk on the floor. Also, the use of a separate platform requires careful placement and centering of the platform and also introduces the need for regularly finding and associating the separate parts.
In U.S. Pat. No. 5,643,154 a relatively squat, rounded ballast is mounted under a relatively wide platform. If the user is willing to stock an inventory, the rounded ballast can be changed, but the individual ballasts are not adjustable. This device is designed for use on land or in water. For use in water, an edge bumper is inflated an adjustable amount to reach the desired buoyance. While this edge bumper is adjustable, this adjustment is only effective in water. The stability of the platform on land will not be substantially affected by adjusting an edge bumper, which inherently provides a stable base. See also U.S. Pat. No. 3,024,021 for a non-adjustable device employing a platform connected through a resilient member to a rounded base.
U.S. Pat. No. 5,643,165 shows a frustroconical balancing device with a flattened apex. This device is stable in only one central position, and becomes highly unstable once titled slightly. Furthermore, the stability of this device is not adjustable. See also U.S. Pat. No. 5,549,536 for a continually tilted platform.
Accordingly, there is a need for an improved device that offers a unique experience and range of possible exercises, and that can allow adjustment, preferably with an inflatable device, to accommodate persons with different levels of skill and capabilities.
The invention is directed to those needs.
One embodiment of the invention is a device for promoting balance. The device has a base to keep the device in contact with a planar surface, such as a floor. The device also has an inflatable flexible portion positioned on top of the base. The flexible portion is structured and arranged such that if it is compressed at a point adjacent but not at the center, the flexible portion exerts a force having a component away from the center of the flexible portion which tends to cause the person to be displaced unless the person exercised sufficient balance to resist the outside force.
Preferably, the inflatable portion is a bladder wherein at certain gas pressures within the chamber of the bladder, the top of the bladder is convex with respect to, and generally circular when viewed from, a point above the device. The volume of the chamber is proportional to the gas pressure.
It is also preferable for the bladder to be anchored to the base at points radially distant from the longitudinal axis of device (where the bladder defines a longitudinal axis generally transverse to the planer surface). The anchored points may be below the center of the top of the bladder. Moreover, for the majority of points along the top of the bladder between the center and the anchored points, as the radial distance from longitudinal axis increases so does the axial distance from the top center point of the bladder.
Another embodiment of the invention also provides a device for promoting balance. In this embodiment, the device has an inflatable flexible bladder defining a longitudinal axis extending through the center of the bladder. The upper and lower surface of the bladder define a chamber and meet at the outer edges. The upper surface of the bladder is structured and arranged so that the highest point of the bladder is at a point between the outer edges, and a user standing on the device has to exercise balance to remain on it. The bladder is also connected to a base at the outer edges.
It is desirable for the device to be generally circular about the longitudinal axis and the base generally cylindrical. It is also desirable for the base to be concave along the longitudinal axis when viewed from a point below the base, and to maintain at least three points of contact with a generally planer surface such as a floor. When the bladder is inflated, the expansion of the bladder causes the center of the base to move towards, but not contact, the planar surface. The lower surface may be generally planer prior to inflation.
Preferably, the device has a plurality of generally annular ridges disposed on the upper surface of the bladder that circumferentially extend around the longitudinal axis. The diameter of the generally annular ridges may be proportional to the gas pressure within the inflatable bladder.
It is also preferable for the bladder to have a hole extending through the bottom surface and connecting the chamber to atmosphere. A removable plug is used to close the bladder hole. In such an instance, the base also has a hole extending from the bottom of the base to the top of the base, the base hole being adjacent to the bladder hole. Preferably, the portion of the bottom surface of the bladder that is adjacent to the bladder hole has a truncated cone shape that extends downwardly into the base hole.
In yet another embodiment of the device, a device for promoting balance has a longitudinal axis and includes: an inflatable bladder having top and bottom surfaces that define a chamber and are joined at edges positioned a radial distance from the longitudinal axis; a rigid base having a top surface, bottom surface and outer edges, the bottom surface intended for placement on a planar surface, and the top surface of the rigid base opposing the bottom surface of the bladder; a clamp circumferentially extending around at least a portion of the base; and a groove defined by the clamp and the base to secure the bladder edges to the base.
Desirably, the outer edges of the bladder define a generally planer circle extending circumferentially around the longitudinal axis.
Optionally, the outer edges comprise a rim meeting one or more of the following conditions: a portion of the rim is below at least a portion of the bottom surface of the bladder; the outermost point of the rim is beyond the outermost point of the bladder top surface; the bottom surface and the top surface of the bladder meet at a point near the top of the rim and the radial width of the bottom edge of the rim is greater than the radial width at that point; the width at the top of the groove is less than width of the rim and the rim is disposed in the groove; the rim has a flange extending upwardly from the top, outer edge of the rim; the rim has a flange extending inwardly from the bottom half of the inner edge of the rim; and the rim has a rim chamber in communication with the chamber of the bladder whereby increasing the pressure within the rim chamber increases the size of the rim.
It is preferable for the clamp to have a side and a top extending inwardly from the side, so that the groove is at least partially defined by the side of the clamp and a portion of the base. Thus, the groove may further have a bottom and an inner side that are defined by the base. A portion of the base may also extend from the inner side and outwardly over the groove and the top of the clamp may extend inwardly over the groove.
In a further refinement of the foregoing embodiment, the outer edges comprise a rim, the rim comprises a first flange extending upwardly from the top outer edge of the rim and below the portion of the clamp extending inwardly over the groove, and the rim comprises a second flange extending inwardly from the bottom half of the inner edge of the rim and below the portion of the base extending outwardly over the groove.
It is desirable for the dimensions of the groove to be sufficient to secure the bladder edges to the base wherein if the clamp is removed from the base, the bladder will not remain secured to the base during use.
The clamp may also include a number of optional features. For example, it may have a rounded ridge extending upwardly from the top, inner-most edge of the clamp. It may also be made of polypropylene, no-break polypropylene or high-density polyethylene. The clamp may also comprise a plurality of separate clamp portions whereby each portion extends less than the entire circumference of the base. Even so, all of the clamp portions collectively may extend around the entire circumference of the base. The clamp portions may be removably affixed to one another by a screw or similar fastener. The clamp portions may also be removably affixed to one another by use of a lap joint. The radial thickness of the clamp may be greater at the lap joint than at the remainder of the clamp, such that the thickness of a clamp portion at the lap joint is approximately equivalent to the thickness of the remainder of the clamp portion.
A further embodiment of the present invention provides a method of manufacturing a device for promoting balance. The steps include: placing an inflatable flexible bladder on a base; placing a first clamp along the outer edges of a circumferential portion of the base in an abutting relationship with a portion of the outer edges of the inflatable bladder; placing a second clamp along the outer edges of another circumferential portion of the base in an abutting relationship with another portion of the outer edges of the inflatable bladder; securing the first clamp to the second clamp and thusly securing the outer edges of the bladder into a circumferential groove defined by the clamps and the base.
In the foregoing method, the first clamp may be removably secured to the second clamp and the method further includes: detaching the first clamp from the second clamp; replacing the bladder with another bladder; and securing the first clamp to the second clamp and thusly securing the outer edges of the other bladder. Preferably, the first clamp and the second clamp collectively extend around a majority, or the entire length, of the outer edges of the base. The clamps may be placed along the outer edges of the base primarily by movement in a direction transverse to the longitudinal axis of the device.
In still another embodiment of the present invention, a method of using a device for promoting balance comprises: providing a device having an inflatable flexible bladder and a base, whereby the center of the top of the inflatable bladder is higher than the remainder of the inflatable bladder and the bladder is above and secured to the base; placing the bottom of the base on a planar surface such that the center of the top of the inflatable bladder is above the base and the planar surface; and standing or moving on the top of the inflatable bladder. Balance is promoted when the bladder tends to direct the user in a direction away from the center of the bladder. By way of example, the step of standing or moving on the top of the bladder may comprise repeated jumping on bladder.
The foregoing device can be made from a variety of materials. For instance, the bladder may be a burst-resistant vinyl, PVC or an elastomeric resin. The hardness of the bladder can reflect the intended use of the device. The bladder may also use a foaming agent.
Preferably, the upper and lower surfaces of the bladder are formed of a single, integral material by the process of rotational molding. It is also desirable for the bladder material thickness to be thicker at the center of the upper surface when uninflated than at the edges. The material thickness at the rim may also be greater than the average material thickness of the bladder.